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BACKPORT: FROMGIT: sched/core: Remove ifdeffery for saved_state

Browse source 
In preparation for freezer to also use saved_state, remove the
CONFIG_PREEMPT_RT compilation guard around saved_state.

On the arm64 platform I tested which did not have CONFIG_PREEMPT_RT,
there was no statistically significant deviation by applying this patch.

Test methodology:

perf bench sched message -g 40 -l 40

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

(cherry picked from commit fa14aa2c23d31eb39bc615feb920f28d32d2a87e
 https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core)
Bug: 292064955
Bug: 304294320
Change-Id: I9c11ab7ce31ba3b48b304229898d4c7c18a6cb2c
[eberman: Use KABI reservation to preserve CRC/ABI of struct task_struct and
 preserved raw_spin_(un)lock instead of new guard(...) syntax in task_state_match]
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
(cherry picked from commit 457e65696a)
This commit is contained in:
Elliot Berman 2023-09-08 15:49:15 -07:00
parent c8bbfb7e22
commit 8095efce6c
2 changed files with 4 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

6
include/linux/sched.h
View file

@ -758,10 +758,8 @@ struct task_struct {
#endif
unsigned int __state;
#ifdef CONFIG_PREEMPT_RT
/* saved state for "spinlock sleepers" */
unsigned int saved_state;
#endif
/* moved to ANDROID_KABI_USE(1, unsigned int saved_state) */
/*
* This begins the randomizable portion of task_struct. Only
@ -1548,7 +1546,7 @@ struct task_struct {
*/
union rv_task_monitor rv[RV_PER_TASK_MONITORS];
#endif
ANDROID_KABI_RESERVE(1);
ANDROID_KABI_USE(1, unsigned int saved_state);
ANDROID_KABI_RESERVE(2);
ANDROID_KABI_RESERVE(3);
ANDROID_KABI_RESERVE(4);

10
kernel/sched/core.c
View file

@ -2255,17 +2255,15 @@ int __task_state_match(struct task_struct *p, unsigned int state)
if (READ_ONCE(p->__state) & state)
return 1;
#ifdef CONFIG_PREEMPT_RT
if (READ_ONCE(p->saved_state) & state)
return -1;
#endif
return 0;
}
static __always_inline
int task_state_match(struct task_struct *p, unsigned int state)
{
#ifdef CONFIG_PREEMPT_RT
int match;
/*
@ -2277,9 +2275,6 @@ int task_state_match(struct task_struct *p, unsigned int state)
raw_spin_unlock_irq(&p->pi_lock);
return match;
#else
return __task_state_match(p, state);
#endif
}
/*
@ -4068,7 +4063,6 @@ bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
*success = !!(match = __task_state_match(p, state));
#ifdef CONFIG_PREEMPT_RT
/*
* Saved state preserves the task state across blocking on
* an RT lock. If the state matches, set p::saved_state to
@ -4084,7 +4078,7 @@ bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
*/
if (match < 0)
p->saved_state = TASK_RUNNING;
#endif
return match > 0;
}